exports.$ = (id) => {
  return document.getElementById(id);
};

exports.convertDuration = (time) => {
  // 转化为分钟
  const minuts = Math.floor(time / 60);
  let second = Math.floor(time - minuts * 60);
  second = second < 10 ? `0${second}` : second;
  return `${minuts}:${second}`;
};
